Abstract

Rationale

In humans, social stress over long and short term can increase alcohol consumption, but the mechanisms involved are not understood.

Objectives

This study was conducted to examine the effects of social defeat, using the resident/intruder paradigm, on the alcohol preference of “low alcohol drinking” individuals in a colony of C57BL/10 strain mice and the effects of two anxiolytic drugs.

Methods

Alcohol preference, in a two-bottle choice (8% v/v alcohol or water), was measured, in separate experiments, after either a single experience of social defeat by a resident male mouse, five consecutive daily defeat experiences or one experience per week for 4 weeks. Comparison was made with effects of repeated social defeat on the preference for dilute sucrose. In addition, the actions of the CCKB receptor antagonist, CAM1028, and of diazepam were examined on the effects of repeated defeat experiences.

Results

Five consecutive daily defeat experiences had a slow onset effect in increasing alcohol preference and consumption, compared with five daily exposures to a novel environment. A single defeat, or one defeat per week, did not significantly alter alcohol preference or intake. There were no effects of five daily defeat experiences on sucrose preference or consumption. The effect of repeated defeats on alcohol preference was significantly decreased by administration of the CCKB receptor antagonist, CAM1028, prior to each experience, but not by corresponding administration of diazepam.

Conclusion

The results show that social stress increases alcohol intake in low alcohol preference C57BL/10 mice and suggest that CCK transmission may be involved in this effect.

Martinez M, Phillips PJ, Herbert J (1998) Adaptation in patterns of c-fos expression in the brain associated with exposure to either single or repeated social stress in male rats. Eur J Neurosci 10:20–33CrossRef